Question

Write assembly code for the following C procedure:

i = 1; sum = 0;

while (i ≤ n) {

sum += i;

++i;

}

i and sum corresponds to $s1 and $s2. n is preloaded into $s3

Answer 1

Hope this will help you. If you have any doubt please let me know.

Notes: You specified only Assembly language based on $s1 and $2 and $s3 register I am assuming you want it in Mips code. I have made 2 versions of this program. In 1^st version n’s value is taken from user while in case of 2^nd version n’s value is predefined. Both are working perfectly fine in Mars tool.

Please let me know if you want any modification in this program.

Commenting is also done with in code.

Please feel free to ask me if you need anything else or you have any doubt.

Please also see the screenshot (for both code 2nd version is simplest)

----------------------------------------------------------------Version1----------------

.text  
   .globl   main  
main:
   # Print string msg1
   li   $v0,4       # printing string syscall code = 4
   la   $a0, msg1   # load the address of msg1
   syscall
  
   # read a input from use
   li   $v0,5       # to read int we need syscall code = 5
   syscall  
   move   $s3,$v0       # syscall results returned in $v0 storing user value into $s3 user input value in $s3
  
   addi $s1,$zero,1 #i's vale in $s1=1
   addi $s2,$zero,0 # sum's value in $s2=0
   loop:
   slt $s4,$s1,$s3 # if i's value is less than n 's value, $s4's value is set to 1 otherwise it is zero
   beq $s4,$0,end #if both are equal jump to end block
   add $s2,$s2,$s1 # adding i's value in sum
   addi $s1,$s1,1 #incrementing i
   j loop
  
   end:
   add $s2,$s2,$s1 # adding a last value of i into sum
  
   # Print string msg2
   li   $v0, 4 #printing sting syscall =4
   la   $a0, msg2 #loading the address of msg2
   syscall  
   # Print output in decimal
   li   $v0,1       # printing a dec syscall code = 1
   move   $a0, $s2  
   syscall
  
   li   $v0,10       # exit
   syscall

   .data
msg1:   .asciiz   "Enter Number that you to store in $s3 (or you want to sum upto that number): "
msg2:   .asciiz   "the sum is= "

---------------------------------------------Version2-----------------------------

   .text  
   .globl   main
  
main:
   add $s3,$zero,5 # $s3 value set to 5 ,you can change value directy from here
   addi $s1,$zero,1 # i's vale in $s1=1
   addi $s2,$zero,0 # sum's value in $s2=0
   loop:
   slt $s4,$s1,$s3 # if i's value is less than n 's value, $s4's value is set to 1 otherwise it is zero
   beq $s4,$0,end #if both are equal jump to end block
   add $s2,$s2,$s1 # adding i's value in sum
   addi $s1,$s1,1 #incrementing i
   j loop
  
   end:
   add $s2,$s2,$s1 # adding a last value of i into sum
  
   li   $v0,1       # printing a dec syscall code = 1
   move   $a0, $s2  
   syscall
  
   li   $v0,10       # exit
   syscall
------------------------------------- screenshot-----------------------